Abstract: Anoplophora glabripennis is a destructive woodborer attacking many deciduous hardwood tree species, especially in northern China. Dastarcus helophoroides parasitizes larvae and pupae of A. glabripennis. Olfactory response of one population of D. helophoroides to larval frass of A. glabripennis from six different host tree species in the genera Populus, Salix, Ulmus and Acer were different, and the larval frass from Acer negundo was not attractive to the population of D. helophoroides. In order to explore the reason that different larval frass of A. glabripennis from different host tree species have different attractive capacities to D. helophoroides, frass volatiles were extracted by solidphase microextraction (SPME) and analyzed by gas chromatographymass spectrometry (GC-MS). The monoterpenes released from frass were extracted by Porapak Q and quantified by gas chromatography. Results showed that terpenes were the major components, and their release amounts differed significantly among the tree species. Among all compounds, ()α-copaene was the only compound that was at a trace level in the larval frass from A. negundo but detectable in the larval frass from the other five tree species. Further Ytube bioassays indicated that ()α-copaene could attract D. helophoroides adults at a low release rate. Therefore, ()α-copaene might serve as the kairomone for D. helophoroides discriminating the larval frass of their hosts feeding on different host tree species.

Key words: nitrate nitrogen level, apple rootstock, ¹⁵N., photosynthesis